JPS6052961A - Disk reproducer - Google Patents

Abstract

PURPOSE:To attain the read-out even for digital signals of a program, data, etc. by adding even an address to a subdigital area of a block containing plural frames of main digital data. CONSTITUTION:A frame synchronizing bit FS of 24 bits, etc. of a specific pat- tern and the 0th-32nd data bits DB(0)-DB(32) of 8 bits, etc. are provided to each of the 0th-97th frames, etc. The bit DB(0) is defined as a subdigital area. The digital audio data, the parity data on error correction codes, etc. are allotted to bits DB(1)-DB(32). A block is formed with each bit of a frame. The block formed with a channel Q of the bit DB(0) includes an address displaying the absolute time of a program area of a disk in addition to the music and the pause time display. The digital signals of data, etc. as well as the program of the bit DB(0) can be read out by giving an access to said address via a CPU, etc.

Description

[Detailed Description of the Invention] "Field of Industrial Application" This invention uses a digital disk on which two channels of digital audio signals are recorded, and stores digital data other than the two channels of digital audio signals. The present invention relates to a disc playback device.

"Background Art and its Problems" A system using an optical digital audio disc (referred to as a compact disc) is a disc system that can reproduce high-quality stereo music. With this disk system, you can record data that represents characters in addition to stereo music without making any major changes to the player's configuration.
Data for display.

If it is possible to reproduce digital data such as program data, by adding a display device, it is possible to realize a device for reproducing visual information such as charts and statistics using graphics, a picture book using still images, and a video game device. The range of applications of the compact disc system can be expanded.

The data storage capacity of current compact discs is approximately 50
It has a storage capacity of 0 MB, which has the advantage of being considerably larger than the storage capacity of conventional flexible disks.

On the other hand, since compact discs are designed to reproduce audio signals, the data on the disc must be cued in relatively large units, such as musical songs or passages. However, as a storage device, I
It is necessary to be able to read data in smaller units such as OK bytes.

"Purpose of the Invention" The present invention provides a method for reading out digital signals such as programs and data instead of digital audio signals by using an existing digital audio disk playback device as is or with only a small portion of the playback device modified. The object of the present invention is to provide a disc playback device that makes it possible to perform the following functions.

"Summary of the Invention" The present invention provides a disc reproducing apparatus using a disc on which main digital data and sub-digital data for selectively reproducing the main digital data are recorded, in which the unit of change in the sub-digital data is an integer. This disc playback apparatus is designed to play back a disc on which a plurality of frames, which are multiples or fractions of an integer, are recorded as one block of main digital data, and a digital signal with an address added to each block is recorded.

"Embodiment" An embodiment of the present invention is an application of the present invention to a compact disc.

The data structure when the signal recorded on the compact 5-day tape is audio data will be explained with reference to FIGS. 1 and 2.

FIG. 1 shows a data stream recorded on a compact disc. One frame is made up of 588 bits of recorded data, and after the frame synchronization pulse FSO of a specific bit pattern for each frame, 3 bits of DC component suppression bits RB are provided, and then each of 14 bits of 0 to 0 is provided. No. 32 data bit DB and 3
The DC component suppression pits RB and RB are provided alternately. The 0th bit in the data bit DB is called a sub-coding signal or user's bit, and is used to control playback of the disc, display related information, etc. 1 to 12゜The 17th to 28th data bits DB are allocated to the main channel audio data, and the remaining 13th to 16th data bits DB are allocated to the error correction code error data of the main channel. Assigned. Each data bit DB
When recording, 8-bit data is converted into 1 by 8-14 conversion.
It has been converted to 4 bits.

Figure 2 shows each data bit D except for the DC component suppression bit.
This shows a state in which 98 frames are sequentially arranged in parallel, with B being 8 bits. The sub-coding signals P-W of frames 0 and 1 form a sync pattern which is a predetermined bit pattern.

Regarding the Q channel, a CRC code for error detection is inserted into 16 frames on the terminal side among the 98 frames.

The P channel is a flag indicating pause and music, and has a low level for music, a high level for pause, and a 2 Hz same-period noise signal in the lead-out section. Therefore, by detecting and counting the P channels, it becomes possible to select and reproduce designated music. The Q channel can perform the same type of control in a more complex manner, for example, by importing Q channel information into a microcomputer installed in the disc playback device and immediately switching to playing other music even in the middle of playing music. Random selection of songs can be performed. The other R channels to W channels are the lyricists and 2 composers of the songs recorded on the disc.

It is used to display explanations, poems, etc., and to provide audio explanations.

Of the 98 bits of the Q channel, the first 2 bits are used as a sync pattern, the next 4 bits are used as control bits, the next 4 bits are used as address bits, and the next 72 bits are used as data bits. , and finally the CRC code for error detection is refined. A track number code TNR and an index code X are included in the 72 data bits. The track number code TNR can vary from 00 to 99, and the index code X can similarly vary from 00 to 99. Furthermore, the Q channel data includes a time display code that indicates song and pause times, and a time display code that displays an absolute time that changes continuously from the beginning of the program area of the compact disc to the end of the outermost circumference. It will be done. Each of these time display codes is a two-digit minute and two seconds.

Consists of frame code. One second is divided into 75 frames. In order to access a compact disc in units shorter than music, such as digital data, the above-mentioned time display code related to absolute time is used.

As mentioned above, in a compact disc, the minimum unit of change in the subcoding signal is 98 frames. In this embodiment, when recording a digital signal other than a stereo music signal, the length of 98 frames from the 0th frame to the 97th frame is one block as shown in FIG. . As described above, one frame includes 12 words of digital audio data, so 24 bytes of digital data can be inserted into one frame. In FIG. 3, one row consists of one sample of the L channel of audio data and one sample of its R channel, which is a total of 32 bits, and each frame has a configuration of six rows.

A sync bit of 1 bit is added to the beginning of each row of 32 bits. Both the first 32 bits of the 0th frame and the leading sync bit of the next 32 bits are set to 0. The leading sync bits of the first 32 bits of even-numbered frames other than the 0th frame are set to O, and the leading sync bits of the first 32 bits of odd-numbered frames are set to 1.

With this sync bit, it is possible to detect the beginning position of a block in units of 98 frames.

One block mentioned above is (24 bytes x 98-2352 bytes). 2 bytes (2048 bytes) of data are inserted into one block, leaving 30 bytes remaining.
It is 4 bytes (=2432 bits). (6×98=588 bits) are used as sync bits. Also, since a 7-bit mode signal and a 24-bit address signal are inserted into the 0th frame (D first (032 bits), 1813 bits remain in one block. These 1813 bits are the data of one block. It can be allocated to redundancy when error correction encoding is performed on the data.

The mode signal specifies the type of data in that block. For example, a mode signal is used to distinguish between character data, still image data, and program code. The address signal is used to specify the data in that block. Furthermore, the reason why the sync bits of even-numbered frames are set to 0 is to take into consideration the case where a data block is configured in units of two frames. In the case of blocks having a size of two frames, a mode signal and an address signal are added to each block. In the case of a block having a length of 98 frames as in one embodiment of the present invention, the absolute time display codes of P data and Q data of sub-coding signals in the same block are the same.

A digital signal in the format shown in FIG. 3 can be recorded on a compact disc in the same manner as for an audio compact disc. That is, a digital signal to be recorded is supplied to a digital input terminal of a digital audio processor, and this digital signal is converted into a video signal form and recorded by a rotary head type VTR. In this case, a TOC (t
(able of contents) data is recorded.

Next, the TOC data reproduced from this magnetic tape is supplied to a subcoding generation circuit, the reproduced digital signal is supplied to an encoder, a subcoding signal is further supplied to this encoder, and the output of the encoder is used to generate a laser beam. Modulate. A master disk is produced using this modulated laser light.

Another method for recording digital signals is to use a minicomputer to access, for example, a node disk memory that can be accessed at high speed, and to supply digital signals in real time to the encoder of the cutting system.

FIG. 4 shows the configuration of an embodiment of the present invention. In FIG. 4, numeral 1 indicates a compact disc on which digital signals of the above format are recorded in a spiral manner. Compact disc 1 has spindle motor 2
is rotated by In this case, the spindle motor 2 is controlled by the spindle servo circuit 3 so that the compact disc 1 rotates at a constant linear velocity.

4 indicates an optical head, optical head 4
is an optical system including a laser source that generates the laser beam for reading, a beam splitter, and an objective lens.

It has a light receiving element for the laser beam reflected by the compact disc 1, etc. The optical head 4 can be moved in the radial direction of the compact disc 1 by a thread feed motor 5. The thread feed motor 5 is driven by a thread drive circuit 6. The optical head 4 has two directions, one perpendicular to the signal surface of the compact disc 1 and the other parallel to it.
The laser beam can be displaced in any direction, and is controlled so that the focusing and tracking of the laser beam during reproduction are always good. For this purpose, a focusing and tracking servo circuit 7 is provided.

A reproduced signal from the optical head 4 is supplied to an RF amplifier 8. The optical head 4 is provided with a focus error detection section consisting of, for example, a combination of a cylindrical lens and a four-part detector, and a tracking error detection section using three laser spots. This servo error signal is supplied to the focusing and tracking servo circuit 7. The output signal of the RF amplifier 8 is supplied to a digital demodulation circuit 9' and a pit clock-regeneration circuit 10. The digital signal recorded on the compact disc 1 is EFM modulated.

EFM modulation is a block conversion of 8-bit data into a 14-bit pattern (i.e., a 14-bit pattern in which the minimum inversion time of the modulated signal is long and its low-frequency components are slightly reduced). This is the way to do it. The digital demodulation circuit 9 is configured to perform EFM demodulation. The pit clock extracted by the pit clock reproducing circuit 10 is supplied to the digital demodulation circuit 9 and the spindle servo circuit 3.

In the digital demodulation circuit 9, the sub-coding signals are separated and supplied to the i9 system controller 11. -System controller 1
1 is provided with a CPU, which rotates the compact disc 1 and feeds the thread.

The reading operation of the optical head 4 and the like are controlled by a system controller 11. The system controller 611 includes an interface 17, which will be described later.
Control commands are supplied via.

That is, the system controller 11 performs control to read a desired digital signal from the compact disc 1 using the subcoding signal.

Main digital data output from the digital demodulation circuit 9 is supplied to the RAM 13 and the error correction circuit 14 via the RAM controller 12. This RAM controller 12, R, AMl 3 and error correction circuit 14
Processing of time axis fluctuation removal, error correction, and error interpolation is performed by terminal 15L.

Main digital data is taken out at 15R.

When reproducing a compact disc on which audio data is recorded, a D/A converter is connected to each of these terminals 15L and 15R. Here, in order to output the digital data as it is, no D/A converter is provided, and the reproduced digital data is supplied to the data conversion circuit 16.

The reproduced sub-coding signal is also supplied to this data conversion circuit 16, and the reproduced data is converted into a serial signal form.

This serial signal is supplied to the interface 17,
Further, data to the system controller 11 is supplied from a microcomputer system 18 via an interface 17. The microcomputer system 18 specifies a read address and supplies control signals such as a start signal to the interface 17 and the system controller 11 in addition to the read address.

A list of a plurality of recording areas is recorded in the lead intratrack at the innermost circumference of the compact disc 1 using subcoding signals as addresses, and this list is played back in the initial state when reading the compact disc 1. and is read by the microcomputer system 18.

FIG. 5 shows an example of the word format of the serial signal output from the data conversion circuit 16.

This serial signal has 32 bits as one word, the first 4 bits are a preamble, the next 4 bits are auxiliary bits of audio data, and the next 20 bits are a digital audio sample. When the digital audio sample is 16 bits, 16 bits are inserted starting from the least significant bit (LSB). Four bits are added after the digital audio sample. Among these 4 bits, the bit indicated by ■ is a flag indicating whether the digital audio sample of the word is valid or not, the bit indicated by U is each bit of the sub-coding signal, and the bit indicated by C is a flag indicating whether the digital audio sample of the word is valid. This is a bit that identifies a channel, and P is a parity bit. The bits of this sub-coding signal are sequentially transmitted with one bit inserted into each word format.

In one embodiment of this invention, a microcomputer is
At step 18, a read command to a predetermined address is executed. This address is the code itself for displaying the absolute time of the Q channel, and is supplied to the system controller 11 via the interface 17. The system controller 11 controls the sled drive circuit 6 and moves the optical head 4 to a position near the target reading position while watching the sub-coding signal reproduced by the optical head 4.

In this example, the reproduced sub-coding signal contains an error, and in order to prevent a malfunction in which the set sub-coding signal is not reproduced and the access operation is not completed, the reproduction is started from a position several blocks away. ing. Then, the target block is captured by matching the reproduced sub-coding signal with the specified address, or by starting reproduction from the correct nearby sub-code signal position and counting frame synchronization signals. I have to.

``Application Example'' A D/A converter and an operation keyboard for the system controller 11 may be added to the configuration of the above-described embodiment, so that a compact disc on which a stereo music signal is recorded can also be played back.

Alternatively, an access code signal encoded with an error correction code may be inserted into another R-W channel in the sub-coding signal.

"Effects of the Invention" According to this invention, it is possible to realize a disk storage device with a much larger capacity than conventional flexible disks, and it is possible to realize a disk storage device that has a much larger capacity than conventional flexible disks, and it is possible to realize a disk storage device that has a much larger capacity than conventional flexible disks. I can do it.

Well, according to this invention, it is possible to improve the error correction method, the signal format such as the recording data format, and the signal processing for discs that cannot reproduce stereo music signals, such as commercially available compact discs. Digital data other than stereo music signals can be recorded while maintaining the sameness. Therefore, by adding a data processing unit such as a microcomputer, a color CRT, and a speaker to an existing disk player using an adapter, it is possible to reproduce various image information and audio information, and it is possible to play back various types of image information and audio information. It is possible to expand the range.

[Brief explanation of drawings]

1 and 2 are route diagrams used to explain the data structure of recorded data on a compact disc to which the present invention is applied, and FIG. 3 is a diagram of one block when recording digital data in an embodiment of the present invention. Route map showing the configuration, No. 4
The figure is a block diagram showing the overall configuration of an embodiment of the invention, and FIG. 5 is a route diagram showing the word format of serial data in an embodiment of the invention. 1... Compact disc, 2...
Spindle motor, 4...Optical head, 5...Feed motor 11
...Tap System Controller, 13...
...RAM, 17...Interface, 18...Tap/Microcomputer system. Agent Masato Sugiura

Claims (1)

[Claims] In a disc reproducing device using a disc on which main digital data and sub-digital data for selectively reproducing the main digital data are recorded, the unit of change in the sub-digital data is an integral multiple or A disc reproducing apparatus is adapted to reproduce a disc on which a plurality of frames divided by an integer are treated as one block of the main digital data, and a digital signal is recorded with an address added to each of the blocks.